Trunking communication systems are mainly used in the field of specialized mobile communication. Available channels of the systems may be shared by all users within the system, having a function of automatically selecting channels. The systems are multipurpose and high-efficiency digital dispatch communication systems capable of sharing resources, sharing the expenses, and sharing channels and services.
According to different dispatch control modes, the trunking communication systems may be classified into centralized trunking communication systems and distributed trunking communication systems. The centralized trunking communication system have specialized control channels and control centers. In an idle state, mobile stations always monitor the control channels, and at ordinary times the control channels maintain long emission states. Every time when a conversation is required, the mobile stations need to send requests to the systems on control channels, waiting for the systems to allocate required service channels. The mobile station is switched to allocated service channels to communicate, and then return to the control channels upon completion of communication. The systems carry out centralized management and allocation of service channel resources through a control center.
The distributed trunking communication systems generally have no dedicated control channel. Any channel in the systems may serve as a service channel and achieve corresponding management and control functions. The mobile station may reside on any channel to communicate.
Due to centralized management of channel resources, the centralized trunking communication systems may better implement sharing and allocation of channel resources and improve a utilization factor of the channel resources. However, to a certain extent the channel resources are wasted because dedicated control channels are required. In addition, this solution is very high in construction and maintenance cost, far beyond bearing capability of many mid-to-low level and small-scale clients.
The distributed trunking communication systems are moderate on scale, low in cost, and needless of dedicated control channels, but need to solve a problem of channel resource allocation and sharing because of having no dedicated control center. Although at present Motorala's Capacity Plus solution solves the problem of channel resource sharing, but a key technology thereof is that a rest channel needs to be set up so that all mobile stations not participating into calls may reside on the rest channel to monitor to ensure called mobile stations may be timely paged. Since all the mobile stations monitor on the rest channel, when a plurality of mobile stations simultaneously launch an access on the rest channel, an access failure may be caused due to collision.
This section provides background information related to the present disclosure which is not necessarily prior art.